EP0748241A1

EP0748241A1 - Rapid exchange dilatation catheter

Info

Publication number: EP0748241A1
Application number: EP95918656A
Authority: EP
Inventors: Georges Boussignac; Pierre Constant Hilaire
Original assignee: Laboratoires Nycomed SA
Current assignee: Laboratoires Nycomed SA
Priority date: 1994-04-29
Filing date: 1995-04-28
Publication date: 1996-12-18
Also published as: WO1995029730A1; NO964569D0; NO964569L; FR2719224B1; AU2449695A; FR2719224A1

Abstract

A dilatation catheter comprising a flexible tubular member with two non-communicating inner lumens. The catheter body (1) further comprises a third inner lumen (8) non-communicating with the first lumen (5) in the region of the balloon portion (2), said third lumen being opened at one end to the outside of the body via a port (9) while its other end is sealingly connected to said second lumen. The third lumen is shaped so that the distal portion of the guidewire remains within said body while leaving the second lumen clear to enable the at least temporary insertion of an other guidewire into said body. The catheter may thus be exchanged rapidly while holding the guidewire in position during stenosis treatment, and the guidewire may be replaced without moving the catheter.

Description

Rapid exchange dilation catheter

The present invention relates to a rapid exchange dilation catheter, intended to be introduced into a body channel such as in particular a blood vessel. The invention is mainly applied in the field of trai ^¬ ment of coronary artery disease but may also be used in the field of treatment of disorders of other body canals, such as the eosophage or urethra.

These affections generally result from the presence, on the internal walls of the canal, of deposits leading to narrowing or stenosis of the latter.

In the treatment of this type of ailments, a dilation catheter is generally used to restore the normal cross-section of the passage of the canal to the level of the stenosis by compression using a balloon (or balloon).

A guide, usually in the form of a wire, is used to facilitate the progression of the catheter to the stenosis.

The guidewire is generally longer than the catheter (of the order of 20 to 50 cm) to allow advancement of the catheter inside the body canal, by sliding along the wire.

A conventional dilatation catheter generally comprises a flexible tubular element comprising a distal part and a proximal part and having at its distal part a radially deformable portion forming a balloon, and at its proximal part a connector. This tubular element comprises a first internal through conduit intended to allow the passage of the guide wire inside the catheter and a second internal conduit, not communicating with said first conduit, opening into the interior of the balloon and connected to a source of fluid supply to allow inflation and deflation of the balloon.

The aforementioned first internal conduit can also be used for the injection, at the level of the stenosis, of various diagnostic or treatment products intended for example to make the restoration of the passage section of the body canal lasting.

During an intervention using a dilation catheter, it may be necessary to change the guide wire, possibly leaving the catheter in position, for example in case of difficulty in progressing inside the coronaries. It may also be necessary to change the catheter, and in this case it is advantageous to keep the guidewire in position.

To remove a conventional catheter, of the type described above (that is to say crossed over its entire length by the guide wire) while maintaining the guide wire in position, it is necessary to have it outside the body longer wire than the catheter.

For example, in the case of a catheter with a length of between approximately 120 and 140 cm and a guidewire with a length of the order of 175 cm, the total length of the wire at course of the exchange procedure should be about 300 cm.

This is why, during the catheter exchange procedure, a special long wire (for example 300 cm) is used to replace the conventional guide wire.

Another known technique consists, during the exchange procedure in adapting to the free end of the guide wire another wire forming an extension (for example with a length of approximately 125 cm).

The patent US 4 827941 incorporated here by reference perfectly illustrates this state of the art.

The use of a specific exchange wire or an extension however makes the exchange procedure more complex.

To avoid this drawback, it has been proposed, in particular in the patent

US 4748 982 also incorporated here by reference, to use a so-called rapid exchange catheter which is crossed by the guide wire only at its distal part, for example over a length of about 20 to 25 cm for a catheter with a total length of approximately 130 cm.

The catheter described in this prior document comprises a distal part comprising two juxtaposed non-communicating internal channels, one of which (intended for the passage of the guide wire) opens out to the outside of the catheter.

Insofar as the catheter is crossed by the guide wire only over a small portion of its length (20 to 25 cm), less than the length of the wire extending outside the body (35 to 55 cm ), it is possible to remove the catheter by sliding it along the guide wire and to replace it with another catheter, without using a specific exchange wire or an extension.

The use of such a catheter simplifies the exchange procedure, but has various drawbacks. First of all, the specific structure of this catheter gives no possibility of exchange of the guide wire.

In addition, this catheter does not have a distal access route for the injection of a diagnostic or treatment liquid at the level of the stenosis. Finally, the workability of the guidewire is poor, insofar as it extends largely outside the catheter.

Under these conditions, the main purpose of the present invention is to solve the technical problem consisting in the supply of a rapid exchange dilation catheter, of a new design, which can be easily produced on an industrial scale, including work is easy, and allowing on the one hand a possible exchange of the guide wire by maintaining the catheter in position and the distal injection of liquid through the internal conduit of passage of the guide wire, and on the other hand a possible exchange holding the guidewire in position.

The solution, in accordance with the present invention, to solve this technical problem consists of a rapid exchange dilation catheter, intended to be introduced into a body channel such as in particular a blood vessel, of the type comprising:

- a flexible tubular body comprising a distal part and a proximal part; - a radially deformable portion forming a balloon, disposed at the distal part of said body;

- A first internal conduit extending longitudinally inside said body, said conduit opening at one end inside the balloon in a sealed manner, and being connected at the other end to a source of fluid supply to allow inflating and deflating the balloon;

- A second internal conduit, passing longitudinally through said body and not communicating with said first conduit, adapted to allow the passage of a guide wire inside said body; characterized in that it further comprises a third internal conduit not communicating with said first internal conduit extending in the vicinity of the portion forming a balloon, opening at a first end outside of said body and communicating at its other end so sealed with said second internal conduit; said third internal conduit being shaped so that the distal part of said guide wire can remain engaged in said body, while freeing said second internal conduit and thus allowing the installation, at least temporarily, of another wire- guide in said body. Thus, the originality of the present invention vis-à-vis the prior art lies in the fact that the catheter body has a third internal conduit whose conformation allows:

- on the one hand, a “classic” rapid exchange operation, that is to say the possibility of changing the catheter without adding an extension or using a special wire, and while maintaining the guide wire in position, the catheter thus being extracted by sliding along the wire;

- on the other hand, a possibility of exchanging the guide wire while maintaining the balloon in position, the conduit 8 then allowing withdrawal of the guide wire in a "waiting position" thus releasing the second internal conduit which allows placing a second guide wire in the body of the catheter.

According to a particular characteristic, the third internal duct of the dilation catheter according to the invention is provided, at its end opening into the second internal duct with a locating means preferably constituted by a radiopaque element such as a metal ring.

This locating means makes it possible to safely position the first guide wire in the standby position in the third internal conduit.

According to another characteristic, the third internal conduit has, at its end opening to the outside of the catheter, the shape of a ramp intended to guide the wire towards the outside of the catheter.

According to a first embodiment of the invention, the above-mentioned flexible tubular body comprises:

- a proximal part in which the aforementioned first and second internal channels extend substantially longitudinally, coaxially; - a distal part in which the aforementioned first and second internal channels extend substantially longitudinally, coaxially;

- An intermediate part providing a tight junction between the proximal and distal parts, and on the proximal portion of which said first, second and third internal conduits are juxtaposed and preferably substantially parallel to one another.

According to a second embodiment of the invention, the above-mentioned flexible tubular body comprises:

- A proximal part in which the aforementioned first and second internal channels are juxtaposed and extend substantially longitudinally and parallel to each other; - a distal part in which the aforementioned first and second internal channels extend substantially longitudinally, coaxially;

Advantageously, in these two embodiments, the length of the distal part increased by that of the intermediate part is less than the length of the guide wire outside the body when the latter is in the position of use.

According to a particularly advantageous characteristic of the invention, the opening of the aforementioned third internal conduit comprises a closure element forming a non-return valve comprising a slot allowing the passage of a guide wire. This conformation ensures stabilization of the guide in the standby position in the third internal conduit.

The invention will be better understood, and other objects, characteristics and advantages thereof will appear more clearly on reading the explanatory description which will follow, made with reference to the appended schematic drawings given solely by way of nonlimiting examples illustrating several currently preferred embodiments of the invention, and in which:

- Figure 1 is a longitudinal sectional view of a rapid exchange dilation catheter according to the present invention;

- Figure 1A is a cross-sectional view along the line AA of Figure 1;

- Figure 1B is a cross-sectional view along line BB of Figure 1; - Figure 1C is a cross-sectional view along the line CC of Figure 1;

- Figure 2 is a view similar to Figure 1 illustrating a first guide wire in the standby position in the third internal conduit;

- Figure 2A is a cross-sectional view along the line AA of Figure 2;

- Figure 2B is a cross-sectional view along line BB of Figure 2; - Figure 2C is a cross-sectional view along the line CC of Figure 2;

- Figure 3 is a view similar to Figure 1 illustrating a first guide wire in the standby position in the third internal conduit and a second guide wire in the position of use in the second internal conduit;

- Figure 3A is a cross-sectional view along the line AA of Figure 3; - Figure 3B is a cross-sectional view along line BB of Figure 3;

- Figure 3C is a cross-sectional view along line CC of Figure 3; - Figure 4 is a view similar to Figure 3 of a rapid exchange dilation catheter according to a second embodiment of the invention;

- Figure 5 is a detail view in longitudinal section illustrating the intermediate part of a catheter according to the present invention; - Figure 6 is a view similar to Figure 5 illustrating an alternative embodiment;

FIG. 7 is a view similar to FIG. 5 without a guide wire, illustrating the shutter element 21.

- Figure 8 is a detail view illustrating the shutter element of the opening of the third conduit.

In the following description, the body canal chosen by way of example is a blood vessel, not shown, such as in particular a coronary artery.

FIG. 1 therefore shows schematically a rapid exchange dilation catheter in accordance with the present invention. This catheter comprises a flexible tubular body 1, comprising a proximal part 1a, an intermediate part 1b and a distal part 1a.

In the example shown, the flexible tubular body 1 has a substantially circular cross section constant over most of its length.

The body 1 has, at its distal part, a radially deformable portion forming a balloon 2, and at its proximal part, a connector element 3.

The connector element 3 is a conventional element with two Y-shaped channels allowing the connection of a balloon inflation system on the lateral channel 4a and the passage of a guide wire in the axial channel 4b. The flexible body 1 can be made for example from one or more semi-rigid thermoplastic materials chosen from polyethylenes, polyamides or else copolymers of the PEBAX® or HYTREL® type.

The radially deformable portion forming a balloon 2 can be integrated into the flexible body 1, as in the example shown, or attached thereto by being fixed therein in a leaktight manner by known means such as for example by heat sealing or by means of a adhesive.

The portion forming a balloon 2 may also be made of a thermoplastic material such as in particular a polyamide, a polyethylene or a polyester. In order to position the balloon 2 at the level of the stenosis (before inflation), the body 1 could be equipped with a locating means such as for example a ring radiopaque metallic 12; a metal such as gold, platinum, tungsten or their alloys which can be used for the production of this radiopaque ring.

In general, the flexible body 1 comprises a first internal conduit 5 extending longitudinally inside said body, this conduit 5 opening at one end inside the balloon 2, in a sealed manner, and being connected to its other end via the connector element 3 to a source of fluid supply, not shown, to allow inflation and deflation of the balloon 2.

The flexible body 1 also includes a second internal conduit 6 passing longitudinally through said body, and not communicating with the first internal conduit 5, this second conduit being adapted to allow the passage of a guide wire inside said body.

In the currently preferred embodiment shown in FIG. 1, the internal conduits 5 and 6 which extend substantially longitudinally inside the flexible body 1 are coaxial in the proximal part 1a (see FIG. 1A) and in the part distal (see Figure 1C).

The proximal and the distal parts are connected to each other in leaktight manner by the intermediate part 1b shown in enlarged view in longitudinal section in FIGS. 5 to 7, and which will be described below. The flexible body 1 comprises, at its intermediate part 1b, a third internal conduit 8 not communicating with the first internal conduit 5, extending in the vicinity of the portion forming a balloon 2, upstream thereof, it is - ie on the side of the proximal part of the body 1 of the catheter.

More specifically, this third internal conduit 8 opens at a first end through an opening 9 outside the body 1 and communicates at its other end, in leaktight manner, with the second internal conduit 6.

Advantageously, the third internal conduit has, at its end which opens out to the outside of the catheter, the shape of a ramp intended to guide the wire towards the outside of the catheter. It should be noted that on the proximal portion of the intermediate portion 1b, that is to say on the length portion over which the third conduit 8 extends, the internal conduits 5, 6 and 8 are juxtaposed (see FIG. 1B ).

The length of the distal part including the balloon portion increased by that of the intermediate part 1b will generally be much smaller than that of the proximal part 1a. In particular, provision will be made, by construction, for a body 1 whose length of the distal part 1a increased by that of the intermediate part 1b is less than the length of the wire remaining outside the patient's body when the said wire is in position of use, that is to say for example when the balloon is located at the level of the stenosis to be treated.

For example, for a catheter with a total length of approximately 130 cm and for a guide wire with a length of the order of 175 cm, the length of the distal part is increased by that of the part intermediate lb will be approximately 20 to 25 cm being specified that the balloon portion will have a length of the order of l to 5 cm.

As can be understood from the preceding structural description, a dilatation catheter according to the invention can be initially mounted in "rapid exchange", that is to say in a conformation as shown in FIG. 1, wherein a guidewire 7 is disposed along the body 1 of the catheter, outside of the latter in the proximal part and inside of the latter in the intermediate and distal part.

In this configuration, rapid catheter exchange is possible, without adding an extension or using a special wire and while keeping the guide wire in position. It is also possible to inject various products up to the stenosis using the second internal conduit 6.

The presence in the intermediate part 1b of the catheter body, of a third internal conduit 8 also makes it possible to exchange the guide wire while keeping the balloon in position. Indeed, the conduit 8 allows withdrawal of the first guide wire 7 in a

"standby position" in the intermediate part lb as illustrated in FIGS. 2, 2A, 2B and 2C.

In order to correctly and securely place the guide wire 7 in the waiting position in the internal conduit 8, a locating means constituted for example by a radio-opaque element such as a radio-opaque metal ring 11, will be mounted at the end of the third internal conduit 8 communicating with the second internal conduit 6 (see FIGS. 5, 6 and 7). This locating means may be made of the same material as the radiopaque ring 12 described above.

As can be understood, when the first guide wire 7 is in the waiting position in the third internal conduit 8, it thus frees the distal part of the second internal conduit 6, and then allows the introduction, at least temporarily, of another guide wire 10 in the body of the catheter.

Of course, the second internal conduit 6 thus released can also be used for the injection of products intended for the treatment of stenosis, or for the introduction of specific instruments such as for example a guide with Doppler type sensor.

FIG. 4 shows a rapid exchange dilation catheter according to a second embodiment of the invention.

In this example, the internal conduits 5 and 6 which extend substantially longitudinally inside the flexible body 1 are juxtaposed substantially parallel to one another in the proximal parts 1a (see FIG. 4A) and intermediate lb (see FIG. 4B) and coaxial in the distal part on (see Figure 4C).

Û should also be noted that in this embodiment, the body 1 also comprises a fourth internal duct 13 extending at the level of the proximal part 1a substantially between the connector 3 and the proximal part adjacent to the opening 9 of the third internal duct 8.

The fourth internal conduit 13 extends longitudinally inside said body 1 substantially parallel to the internal conduits 5 and 6, which in the proximal part 1a are juxtaposed and parallel to one another. This fourth conduit allows to introduce into the proximal part of the body

1 of a catheter an element intended to stiffen this part, produced for example in the form of a metal rod 14.

Referring to Figures 5 to 8, we will now describe in more detail the structure of different embodiments of the intermediate portion 1b of a rapid exchange dillation catheter according to the invention.

In the embodiment shown in Figure 5, the internal conduits 5 and 6 extend coaxially in the proximal part la.

More specifically, the flexible body 1 is defined by an external envelope 15, the second internal conduit 6 disposed in a substantially central manner is defined by a wall 16 while the first internal conduit 5 which is arranged radially and externally relative to the internal conduit 6 is defined by a wall 17.

The proximal part la is extended in leaktight fashion by a sleeve comprising three substantially parallel and juxtaposed internal channels, one of which defines the third internal conduit 8 and the two others communicate respectively with the internal conduits 5 and 6 of the proximal part described above. A radiopaque marker 11 consisting of a metal ring is disposed at the distal end of this sleeve.

Beyond this sleeve is a part ensuring a tight junction with the distal part 1c of the catheter, in which the internal conduits 5 and 6 are again coaxial as in the proximal part 1a.

In fact, the internal conduits 8 and 6 meet beyond the aforementioned sleeve so as to form only one conduit 6 in the distal part.

Figure 6 is a detail view of the intermediate portion 1b of a rapid exchange dilation catheter according to the second embodiment of the invention described above.

In this embodiment, the proximal part 1a consists of a tube comprising three juxtaposed channels respectively defining the first, second and fourth internal conduits 5, 6 and 13 defined above.

A stiffening element 14 is shown in the conduit 13. This three-way tube continues in the proximal portion of the intermediate part 1b, thus defining the first, second and third internal conduits 5, 6 and 8 defined above.

The internal conduit 8 extending the fourth internal conduit 13 is separated from the latter by an element 20 defining a ramp at the abovementioned opening 9.

This element 20 is also present in the embodiment described in FIG. 5.

In FIGS. 5 and 6, one can see a guide wire 7 placed in the waiting position in the third internal conduit 8, and a second guide wire 10 mounted inside the second internal conduit 6.

Figure 7 is a view similar to Figure 5 illustrating an alternative embodiment of the intermediate portion 1b of a rapid exchange dilation catheter according to the invention.

In this alternative embodiment, the opening 9 of the third internal conduit 8 comprises a closure element 21 forming a non-return valve and comprising a slot 22 allowing the passage of a guide wire 7.

This sealing element can be produced for example in the form of an elastomer membrane such as for example a silicone, polyurethane or PEBAX® membrane. The slot 22 will be made without removal of material, so as to form a non-return valve for the injection liquids which can be used for the treatment of stenosis.

In addition, the membrane 21 will ensure, thanks to this slot 22, the stabilization of the guide in the standby position.

The catheter which has just been described can be used in a completely conventional manner and those skilled in the art can refer to the existing literature with regard to its positioning inside the body canal.

Claims

1. Rapid exchange dilation catheter, intended to be introduced into a body channel such as in particular a blood vessel, of the type comprising:

- a flexible tubular body (1) comprising a distal part (le) and a proximal part (la) and comprising:

- a radially deformable portion forming a balloon (2), disposed at its distal part;

- a first internal conduit (5) opening at one end inside the balloon in a leaktight manner, and connected at the other end to a source of supply of fluid to allow the inflation and deflation of the balloon;

- a second internal conduit (6), passing through, not communicating with said first conduit (5), adapted to allow the passage of a guide wire (7) inside said body; characterized in that said body (1) further comprises a third internal conduit (8) not communicating with said first internal conduit (5) extending in the vicinity of the balloon portion (2), opening at a first end by a opening (9) outside said body and communicating at its other end in a sealed manner with said second internal conduit; said third internal conduit being shaped so that the distal part of said guide wire can remain engaged in said body, while freeing said second internal conduit and thus allowing the installation, at least temporarily, of another wire- guide in said body.

2. dilation catheter according to claim 1, characterized in that the aforementioned third internal conduit (8) is provided, at its end opening into the second internal conduit (6), with a locating means.

3. dilation catheter according to claim 2, characterized in that the aforementioned locating means is constituted by a radiopaque element such as a metal ring (11).

4. Catheter according to one of claims 1 to 3, characterized in that the aforementioned third internal conduit (8) has, at its end opening to the outside of the catheter, the shape of a ramp intended to guide the wire to the outside of the catheter.

5. dilation catheter according to one of claims 1 to 4, characterized in that the aforesaid flexible tubular body (1) comprises: - a proximal part (la) in which the first and second internal channels (5, 6) mentioned above extend substantially longitudinally, coaxially; - a distal part (le) in which the aforementioned first and second internal channels (5, 6) extend substantially longitudinally, coaxially;

- An intermediate part (lb) providing a sealed junction between the proximal (la) and distal (le) parts, and on the proximal portion of which said first, second and third internal conduits are juxtaposed and preferably substantially parallel to one another.

6. dilation catheter according to any one of claims 1 to 4, characterized in that the aforesaid flexible tubular body (1) comprises:

- a proximal part (la) in which the aforementioned first and second internal channels (5, 6) are juxtaposed and extend substantially longitudinally and parallel to each other;

- a distal part (le) in which the aforementioned first and second internal channels (5, 6) extend substantially longitudinally, coaxially;

7. dilation catheter according to claim 5 or 6, characterized in that the length of said distal part (le) increased by that of the intermediate part (lb) is less than the length of the guide wire outside the body when it is in the use position.

8. dilation catheter according to claim 7, characterized in that the aforesaid flexible tubular body (1) further comprises a fourth internal conduit (13) extending at its proximal part (la) for introducing an element intended to stiffen this part, produced for example in the form of a metal rod (14).

9. dilation catheter according to any one of the preceding claims, characterized in that the opening (9) of the aforementioned third internal duct (8) comprises a closure element (21) forming a non-return valve comprising a slot ( 22) allowing the passage of a guide wire.